Increased γ‐Aminobutyric Acid Receptor Function in the Cerebral Cortex of Myoclonic Calves with an Hereditary Deficit in Glycine/Strychnine Receptors

Abstract

Inherited congenital myoclonus (ICM) of Poll Hereford cattle is a neurological disease in which there are severe alterations in spinal cord glycine‐mediated neurotransmission. There is a specific and marked decrease, or defect, in glycine receptors and a significant increase in neuronal (synaptosomal) glycine uptake. Here we have examined the characteristics of the cerebral γ‐aminobutyric acid (GABA) receptor complex, and demonstrate that the malfunction of the spinal cord inhibitory system is accompanied by a change in the major inhibitory system in the cerebral cortex. In synaptic membrane preparations from ICM calves, both high‐ and low‐affinity binding sites for the GABA agonist [3H]musc..